Disable login prompt

**Is your feature request related to a problem? Please describe.**
Every time I [re]launch vscode or reload a window I am prompted to "Sign in to GitHub to access your repositories and GitHub Actions workflows."

**Describe the solution you'd like**
Add an option to disable this prompt.

**Additional context**
Shortly prior to the official adoption of this extension, progress was made on the original repo to allow the relevant parts of the extension (syntax highlighting, public action tooltips, etc) to function without logging in. That left it in the current state, with those features working, but the prompt still always popping up.

首先定位 VS Code 扩展的登录提示，以及支持在未进行身份验证的情况下使用语法高亮和公共操作工具提示的现有路径。确定扩展选项可以控制提示的位置，然后验证禁用该选项会抑制重复的登录请求，同时这些未身份验证的功能仍可继续工作。

由索引模型根据 Issue 内容生成。